The ‘Twigstrument’ is an electroacoustic bowed twig instrument, which I created for use in Bastard Assignments’ PIGSPIGSPIGS. It evolves Michael Ridge’s design for an ‘earth block instrument‘ (with Ridge’s permission, of course) based around a metal earth block (holding the twigs securely so they can be bowed) attached to a box, inside of which is a contact microphone picking up the vibrations created by bowing the twigs. My alterations are to embed a Bela Mini nanocomputer, programmed using Pure Data to process the sound of the twigs, inside the box, adding a Bela Trill Bar touch control to one panel to give touch control of some software parameters directly from the instrument itself, and most recently to incorporate 2 LED indicators to visually represent states which are controlled by the Trill Bar.
Currently, the Trill Bar offers controls to mute and unmute the instrument (especially useful to eliminate handling noise when picking it up and putting it down), change the volume and reset volume and mute states in case of problems. The only processing being carried out on the sounds for PIGSPIGSPIGS is to add reverb and volume adjustments, but the possibilities for programming additional effects in Pure Data (or the other programming languages the Bela Mini supports) are vast. The Pure Data code currently in use on the Twigstrument (March 2025) is available to be downloaded from https://github.com/ZubinKanga/Twigstrument.
“The sound is surprisingly sweet, almost ethereal,” wrote Robert Barry in his March 2025 profile of Bastard Assignments for The Wire – but it can also be harsh, like the howls of the damned, and everything in between, veering between delicate and brutal. The challenge of performing this instrument is that the twigs are never the same twice. They break, get reinserted in their shortened forms, discarded, and just replaced. Willow and goji have been the most successful woods I have tried so far. The willow was Ridge’s recommendation: it provides a wide range of sounds, from high, bell-like pitches to deep lowing sounds and shuddering tones when bowing far from the point of connection at the earth block. Goji was… convenient – in my garden – but seems to provide clear pitches, so that by combining the two woods (usually 3 willow, 1 goji), I can be confident of ending up with both pitches and noise to play with.
The current Twigstrument is a prototype, which I have made inside a papier maché gift box. The box contains:
- 1 Bela Mini
- 1 Trill Bar touch control
- 1 mobile phone power bank (5V), connected to the Bela Mini via USB
- 1 small circuit connecting 2 LEDs (yellow and white) to the Bela Mini
- 1 contact mic (currently my JrF contact mic plus an adaptor to connect it to Bela’s 3.5mm audio input).
Developments planned for the twigstrument in 2025 include:
- Making my own contact mic, so I can have a mic that is permanently affixed to the instrument and can reduce the length of the cable in the box
- Making a wooden box for the instrument, being more in keeping with the natural-world implications of the twigs, which feels appropriate for its use in PIGSPIGSPIGS as well as looking better than the prototype box.
- Making a replacement for the earth block, using the same principles but offering more and larger holes, which I hope I will be able to lay out along a curve, similar to the bridge on a violin or viola, which should allow the performer access to all the twigs individually.
The Twigstrument made its first public appearance in a very early version of the prototype at Fourth Portal’s drone performance event in Gravesend on 31 August 2024. It will feature in performances of Bastard Assignments’ PIGSPIGSPIGS across 2025 and 2026, starting with this work’s premiere at Borealis – a festival for experimental music in Bergen, Norway on 15 March 2025.
The development of this instrument has been supported by Borealis – a festival for experimental music, Spor Festival and Wigmore Hall as co-commissioners of PIGSPIGSPIGS; Arts Council England; and Cyborg Soloists who have lent me the Bela Mini nanocomputer used in this project.